The mechanism of the toxicity of sytrene will be elucidated. The tissue distribution, pharmacokinetics and metabolic effects of isomers of polychlorinated biphenyls will be studied. Effects of drug metabolizing enzymes of polychlorinated benzenes, phenols, and terphenyls, which all constitute major environmental pollutant groups will be investigated. Isomers of PCB's will be used to clarify the interdependence of different drug biotransformation reactions. Preliminary studies indicate that heavy metal salts can be used as tools in the study of monooxygenation and conjugation reaction activities in vitro. The effects of heavy metal salts will (Cd, Hg, Pb, Co) be studied on the activity of UDP glucuronosyltransferases, glutathione S-transferases and epoxide hydrase. The studies of the effects of cigarette smoke on the pulmonary metabolism of steroids and vasoactive hormones will be continued. The maturation of these reactions in the fetal lungs will be studied. The role of gluronide conjugation in the pulmonary metabolism of benzo(a)pyrene will be evaluated.